Extraction Of Black Rice Protein And Functional Properties And Modification Of Glutenin

Black rice,also known as purple rice,is a kind of edible rice.Because its skin is black,it is called black rice.Black rice contains special ingredients such as VC,chlorophyll,anthocyanin,carotene and cardiotonic.China is the country with the richest resources of black rice and has a planting history of more than 2,000 years.At present,there are many researches on the extraction and properties of rice protein and rice residue protein.At present,there are many researches on the extraction and properties of rice protein and rice residue protein.In this paper,black rice was used as raw material to study the function and structure of black rice protein fractionation and black rice gluten.The study on the modification of black rice gluten by enzymatic hydrolysis,glycosylation and enzymatic hydrolysis-glycosylation,chang the structure of black rice gluten and increases solubility and emulsification.The main research contents are as follows:(1)Four kinds of proteins were extracted by osborne of black rice protein,which were albumin,globulin,prolamin and gluten.The relative percentages of the four proteins were 12.61%,3.41%,1.24% and 82.75%,respectively.(2)In terms of functional properties,black rice gluten has higher solubility,emulsifying and emulsion stability than rice gluten and lower than soy protein.In terms of structure,black rice gluten contains 17 kinds of amino acids,the secondary structure consisted of 5.15% ?-helix,40.65% ?-sheet,21.70% ?-turn and 32.40%unordered of the black rice gluten.The molecular weights are mainly distributed at 11 kDa,15 kDa,20 kDa,33 kDa,45 kDa,90 kDa,115 kDa,125 kDa and above 200 kDa.(3)Protease digestion of black rice gluten with trypsin,papain and alkaline.Arabinose,maltodextrin,sodium alginate and lactose are glycosylated with black rice gluten,respectively.Trypsin digests black rice gluten and reacts with arabinose.These modification methods increase the emulsification and emulsion stability of the protein.Among them,the solubility and emulsifying properties of the product obtained by enzymatic hydrolysis-grafting for 120 min were the greatest.(4)The structure of black rice gluten was compared with the three modified products,and the denaturation temperatureof the modified protein was increased.It was found by SDS-PAGE that the enzymatically hydrolyzed black rice gluten was decomposed into small molecules,and the glycosylation showed macromolecularbands.A part of the sugar chain is introduced,and the enzymatic hydrolyzed product appears at the largest molecule after the glycosylation reaction,indicating that the macromolecular migration;infrared spectroscopy and circular dichroism indicate that the black rice gluten structure changes,and the modified product has a ?-sheet structure.The reduced content increases the structural content of other stretches.